Catalytic structure of silica on alumina-coated porcelain



Patented Jan. l, 1952 e No Drawing. uApplieationfseptembexn23, :11949,

serial- Nn. '117,489

:catalystV "suitable for use in the conversion 'cit a relatively hlghboiling."hydrdcabo *fraction 'fiO a relatively AW" boiling hydrocarbon n"fxalrsiriijl, .being especially .adapted for use"inthejprocc$s .forming the subject" "matter 'cF-.fan` :applicatiqn "Second: -weAll dippedactive aiuminaplletsliintcfan Ast-cante.seeninzthe-case o'f addition of silica *asv inflame- .136559Z Gasclinei to active alumina pellets, the cracking activity` increases as tthe"'ratiowofnthe---Siz to AlzOiincreasesand acatalyst having an A1203 .to .S102 ratio n'of "32'`:"1 wim-30.6% weight'oi *the A1205) gave the following results:

Gasoline 'percent volume ijf the ycharge.. 38.4

catalyst having a ratio or A1203 tdsb:

#Gasoline 1s-percent volume foi Itii'e charge.; `TI

Cokewww-c-..sw---washes-silosn .mterpoiaticn of the above results totheff'sanie 'gasoline yield gives 1"the ffollclwing` vco'n'uiarisl'inv fo f yTil! "as :presently used; in commercial "xedzbed units:

Gasi-- .percentaweight iof the charges products obtainedz Per "Cent as Ook iCatalytic"activity: indices l in commercia1-ns inl' moving bed: units and `.from 20-125.'in.:iot1i'ex 'unitsr using `cracking catalysts.

.Eorffallpractical @purposes dt :"cannb'e esately fstated from ithe l'above results that/'the ujf vcrackingacatalysts' in which the 1alumina-is in :exf

.fcess 'of the silica willinsure 11a vsaving.f of 530-to 40 percent in the cokellformation -for thevsamegyield fof gasoline.

l"lheygas quality in the case of :the 'lowtpe'noent- :agewsilica-x catalyst lis :slightly fabove'llthe quality of lth'e gas lproduced` withthe A standardfsynt'hetic alumina-silica catalyst. i y

cAs ,anexample of the. method of preparation .of @such `a catalyst, a weighed amount of activeluymina' in; pellet for-m 3-1 mm. diameterx 43 having porosity `in theyrange of 'S0-40% ,is :oven driedv4 at220? F. and then immersed in ltlyl .ortho silicate @until tlie'pelletsare saturated with the liquid. The vpel-lets are .then removed andthe concentrations vo'f "silica'the V"above" procedure' ls duplicatecl `'as many :times as 'required tcvlitain the" 'desired v,activity of "the catalyst.

hydrocarbons Ytd 'low boiling hydrocarbons, i'since.

vwhile it gives an active catalyst, one of the components, namely, the activated alumina, serves as a support, and the only support, for the silica; that is, the catalyst; is self-supporting. It is, however, devoid of the strength necessary to maintain it self-supporting. The pellets quickly fall to powder. For this reason, their use in the moving bed catalytic process is obviously out of the question, and even in the fixed bed process the effect would be the same, that is, the pellets would soon fall to powder.

Y In order to adapt our process to the manufacture of a catalyst structure and apparatus intended particularly for use incatalytic cracking, we first produce a catalyst structure comprising a support of porcelain, or any equivalent support which, like porcelain, is relatively impervious, physically resistant, and capable of sustaining temperature shocks, and that is itself inert as a catalyst. The support is preferably in the form of a rod, coated with active alumina, in

accordance with the process described. in an ap- Serial No. 157,413.

y For example, assuming that the inert porcelain support is in the form of a rod, or of a multiplicplication iiled by Louis E. Malina, April 21, 1950,

ity of rods closely associated and spaced apart,I I

or sulfate solution of the base) composed of 635 grams of aluminum nitrate per 1000 cc. of water. Thepowder and the liquid are thoroughly mixed 'and ground together in a pebbled ball mill, after which a heterogeneous solution of aluminum nitrate and alumina powder is obtained. The porcelain'rod is then immersed in the solution for a period of (say) one minute. The rod is then air dried for (say) ve minutes, then oven dried at a temperature of about 220230 F. and then heated slowly for about one hour to a temperature of (say) 800 F. and cooled gradually to room temperature. To give the alumina nlm the necessary strength and secure its adherence to V'therod one or more similar clippings may be necessary, each followed by successive heatings and subsequent'cooling as described. While this condensed description is all that is required to enable one skilled in the art to produce the aluminacoated rod, Vthe said application describes the process in more detail, a more extended treat' ment beine'r required if the porcelain has some degree, e. g., ten per cent, of porosity.

..`..I'he active alumina coating is then impreg` nated with silica, as hereinbefore described. The

ratio of silica to alumina should 4be from 1:2 to

1:5; or it may be as low as 1:10. lThe thickness of the aluminasilica combination. on the inert porcelain support should be such that the `pro-A portion of 'the former to the latter by volume shouldbe between 20 and 50 per cent., preferably on the order of 30 percent. For example, a porcelain rod having a diameter of Ik may have a thickness of preferably .011, but may vary from V(say) .008 to .014". VWhat is claimed is: l..The process of manufacturing a catalyst structure and composition which comprises applying to an inert porcelain support a coating of active alumina and impregnating said, coating with silica i-n a proportion of between 1 silica to l0 alumina and 1 silica to 2 alumina..

2'. T he process of manufacturing a catalyst structure and composition which comprises applying to an inert porcelain support a coating of active alumina and impregnating said coating with silica in aproportioniof between 1 silica to l0 alumina and'l silica to 2 alumina until the thickness of the alumina-silica combination on the inert porcelain support is such that the pro- Y mina and lsilica to 2 alumina, the thickness of the alumina-silica combination on the inert porcelain support being such that the proportion of the former to the latter by volume is between 20 and. 50 per cent.

5. The process of manufacturing a catalyst structure which comprises adding finely divided alumina to a saturated solution of aluminum niv trate and grinding to produce a heterogeneous solutionof aluminum nitrate and finely divided alumina, applying said solution to a film support of catalytically inert porcelain, subjecting` the coated porcelain tofthe temperature required to leave on the porcelain support a. film of active alumina, and impregnating said coating with silica until the ratio of silica to alumina is ybetween 1:10 and 1:2.

46'. A catalyst structure and composition adapted for use as a catalyst in the cracking of hydrocarbons which comprises a multitude of closely associated, but spaced apart, catalytically inert rods coated with alumina impregnated with silica in a proportion between 1 silica to l0 alumina and 1 silica to 2 alumina. 7. The process of manufacturing a catalyst structure which comprises adding nelydivided alumina to a saturated solution of aluminum nitrated and grinding to produce a heterogeneous solution of aluminum nitrate and nely .divided alumina, applying said solution to a lm support of catalytically inert porcelain, .subjecting the coated porcelain to the temperature required to leave-on theporcelain support a ilm of active alumina,vapplying to the alumina nlm-.coated porcelain support an organic compound contairn ing silica until the alumina is saturated, draining off excess liquid, heating the silica-impregnated alumina film to the yrelatively low temperature required to `remoye the moisture, heating the silica-impregnated alumina lm in an oxidizing atmosplierfe'jto: the,v temperature. required to decompose the organic silicate and permit the silica to react with the alumina, and repeating the operationluntil the'ratio of silica to alumina is between 1:10 and 1:2. i

j EUGENE J. HOUDRY.

JAMES W. HARRISON.

REFERENCES CITED The following .references are of record in the file of this patent:

v.UNITED STATES PQI'IENTS Number Name Date 1,939,647 "Arnold et a1 Dec. 19, 1933 2,242,627 Strickland May 20, 1941 2,394,796 Marisic Feb. 12, 1946 2,493,896 Parde'e et al. Jan. 10, 1950 

7. THE PROCESS OF MANUFACTURING A CATALYST STRUCTURE WHICH COMPRISES ADDING FINELY DIVIDED ALUMINA TO A SATURATED SOLUTION OF ALUMINUM NITRATED AND GRINDING TO PRODUCE A HETEROGENEOUS SOLUTION OF ALUMINUM NITRATE AND FINELY DIVIDED ALUMINA, APPLYING SAID SOLUTION TO A FILM SUPPORT OF CATALYTICALLY INERT PORCELAIN, SUBJECTING THE COATED PORCELAIN TO THE TEMPERATURE REQUIRED TO LEAVE ON THE PORCELAIN SUPPORT A FILM OF ACTIVE ALUMINA, APPLYING TO THE ALUMINA FILM-COATED PORECELAIN SUPPORT AN ORGANIC COMPOUND CONTAINING SILICA UNTIL THE ALUMINA IS SATURATED, DRAINING OFF EXCESS LIQUID, HEATING THE SILICA-IMPREGNATED ALUMINA FILM TO THE RELATIVELY LOW TEMPERATURE REQUIRED TO REMOVE THE MOISTURE, HEATING THE SILICA-IMPREGNATED ALUMINA FILM IN AN OXIDIZING ATMOSPHERE TO THE TEMPERATURE REQUIRED TO DECOMPOSE THE ORGANIC SILICATE AND PERMIT THE SILICA TO REACT WITH THE ALUMINA, AND REPEATING THE OPERATION UNTIL THE RATIO OF SILICA TO ALUMINA IS BETWEEN 1:10 AND 1:2. 